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断层构造失稳突变诱发冲击地压机制研究

Study on mechanism of rock burst induced by sudden instability of fault structures

  • 摘要: 为研究断层区域附近发生冲击地压的机理,分析了断层倾角、断层切向刚度、侧压系数和水平构造应力等地质因素对断层面应力场演化和滑移量突变的影响特征,总结了断层瞬时失稳诱发冲击地压的前兆信息。结果表明,工作面回采过程中断层面上切应力和滑移量随断层倾角先增大后减小。当断层倾角为45°时,断层面上切应力和滑移量最大;断层切应力随断层切向刚度和侧压力系数的增加而增大;水平构造应力作用下,当工作面距前方断层30 m内,断层面上切应力最低。工作面过断层时对断层扰动极大,断层切应力激增。在距离达到5 m时,断层滑移速率绝对值突增,滑移量陡增,为滑移突变危险区域。因此,当断层面上切应力或滑移量在逐渐降低过程中突然激增可作为冲击地压发生的前兆信息。

     

    Abstract: In order to study the mechanism of rock burst in the fault-influenced zone during coal mining,the influence of geological factors,such as fault inclination,tangential stiffness,lateral pressure coefficient and horizontal tectonic stress on the stress distribution and the amount of slip in the fault zone has been analyzed. In addition,the precursory information of coal burst induced by sudden fault instability has been summarized. The results show that with the increase of the dip angle,the shear stress and the amount of slip of the fault zone increases and then decreases. When the angle of the fault is 45°,they reach the peak value. The shear stress and the amount of slip of the fault zone with the increase of the tangential stiffness and the lateral pressure coefficient of the fault are increasing. Under the action of horizontal tectonic stress,when the fault is within 30 m,the shear stress on the fault plane is reduced to the lowest,When the working surface passes through the fault,the disturbance is very large,and the shear stress suddenly rises. When the distance from the fault is within 5 m,the fault slip and slip rate also exist the same law. Therefore,the suddenly rise phenomenon can be used as the precursor information of coal burst when the shear stress on the fault plane or the amount of fault slip gradually decrease in the process of coal mining.

     

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